text:
Do some flying techniques wear aircraft out quicker than others?
In the 2012 film Flight, the cause of the mechanical failure is a sort of worm-screw that controls the rear tailplane. And I believe that in real life failures in those devices have been implicated in one or more crashes, with people shocked that there were no fail-safe mechanisms.
Do airline pilots feel or have a responsibility not to subject a machine to extreme mechanical stresses? Or is the assumption that nothing they can really do has not been foreseen by the designers?
Do some individual flying techniques, used by pilots, wear aircraft out quicker than others?

Full context:
This 2012 film, with Denzel Washington, aired last night on UK TV.
I think I have seen bits of it before... this time around for various reasons I also missed a small part of it.
If you haven't seen the film this question might not be of interest.  If you have, and you're interested in flying, you probably remember it: it involves a "hero pilot" implausibly "inverting" a commercial airliner which is plummetting downwards, and eventually doing a crash landing where most people walk out alive.
One of the main "themes" of the film is that the pilot, played by Denzel Washington, is a "maverick": he is an alcoholic and cocaine-snorter, etc. He is drunk when he gets on the plane, and drinks more during the flight.
The thing that I'd like to ask about is this: the cause of the mechanical failure is a sort of worm-screw which controls the rear tail plane... and I believe that in real life failures in these devices have been implicated in one or more crashes, with people shocked that there was no failsafe mechanism, etc.
But another aspect of the film is the very "dramatic" take-off: the plane takes off in a very bad storm, and "Denzel" takes the plane through some very macho manoeuvres in order to get out of the "bad air" and find some "good air".  The passengers are terrified and the plane is rolling all over the place, while the co-pilot is saying that the plane is flying too fast.
The "investigation" sequence of the film, which is the bulk of it, never seems to pose the question about the advisability of "macho" flying techniques and the possibly culpability of a pilot when taking a plane to its mechanical "limits".  The clear position of the film is that the aircraft was simply "bad" (and recommended maintenance procedures hadn't been followed, etc. etc.).
Do pilots flying commercial airliners feel or have a responsibility not to subject a machine to extreme mechanical stresses, as far as is humanly possible, or is the assumption that nothing they can really do has not been foreseen by the designers?  Do some individual flying techniques, used by commercial pilots of passenger aircraft, wear aircraft out quicker than others?

Practically speaking it's really hard to enforce any rules to the user, any product included. A lot of times the cost of such enforcement mechanism is so expensive that it's just not implemented, but only documented. E.g. the machine would not prevent certain operations but the manual says those operations should not be performed. Personally I believe for any product, not limited to aircraft, there are far more ways it could be used than it should be used.

So, first of all designer can not foresee all the possible uses, misuses, and abuses of the product, also for the things the did foresee, very often they lack the means to prevent them.

Aircraft failures used for training that suffer abnormal numbers of poorly handled takes offs & landings have been ruled not justifiable cause for several AD's. Float planes may cause specific wear or excessive corrosion that would otherwise be worthy of AD's. Pressurized commercial aircraft are required to track pressurization cycles and may be forced to retire early if they have been used for short trips. Hawaiian Air has been forced to retire jets early because most of their routes only last 30min with an abnormal number of T/O and landings.

Let’s start out by agreeing that “Flight” got lots and LOTS of details very very wrong in more ways than 1 thread can list.  Any pilot who did a tiny fraction of what the “hero” does in that movie would be reported, and drug/alcohol tested, and fired, in very very short order.  Whoever decided to write a script with that sort of thing going on as its premise, has his head planted very firmly in an alternate reality to the one that the rest of us live, and fly, in.
That out of the way, let’s talk about the specific questions asked, starting with the “dramatic takeoff.”  In the military, there can be missions where “you do have to go out, you don’t have to come back” — i.e. your chances of survival may not be very good, but this is war & you’re going to launch. In the airline world, the reverse is the case: takeoffs are optional, landings are mandatory.  If you don’t see the path for the whole flight being completed safely, you don’t take off. Period, dot, end of story.  There is no airline flight out there these days that is “the last flight out of Saigon” (where you’re going to attempt the takeoff because the alternative is just too awful).  If the weather around your departure airport is dangerous, then you wait until it isn’t.  If you think you’re going to need “macho maneuvers” to get out of town, you have no business taking off.
There will be times when what looked like a decent ride turns out not to be, or you knew that the ride would be somewhat bumpy & things turn out to be worse.  That’s the limitation of how much information you have about the atmosphere.  And yes, you will be working to find a better ride.  However…

There is nothing particularly exciting about finding a better ride — it’s simply the same sort of climb or descent that’s used getting to and from cruise altitude. And changing course to find a better ride will be the same 20-30 degree bank turn that everything else is maneuvering the airplane. Nothing dramatic, nothing macho, nothing wild.
Also, if the unexpectedly bad ride scares the passengers, well, that’s the way things can go, but if what the PILOT is doing is scaring the passengers, then HE IS SCREWING UP!  There is essentially no scenario you can come up with where doing something that scares the passengers is the right answer.  If you got to the point where something “scary” is required to avert disaster, then either you’ve had the one-in-a-million combination of bad things happening to you, or else you screwed up by letting yourself get to that point.  (Okay, rolling inverted in the movie to control the uncontrollable pitch is in that sort of category. Could that have actually worked for the Alaska flight? No idea. But that’s how creative you have to get to come up with any sort of scenario which such crazy behavior makes sense.)

If the copilot is telling the captain that he’s flying too fast, then one of two things is going on: either the copilot doesn’t understand what is & isn’t “too fast” (which can happen), or else the captain is, in fact, flying too fast.  And any captain that makes very many copilots uncomfortable like that is going to be having a talk with his Chief Pilot before very long.

“Do pilots flying commercial airliners feel or have a responsibility
  not to subject a machine to extreme mechanical stresses…?”

Yes, absolutely. And the Flight Data Recorder will record what happens. If you do something that grounds an airplane for an inspection and/or repairs, you’ll probably be explaining yourself to somebody before too long.  More than that, you have a responsibility to your passengers to give them a safe flight, as comfortable as possible, with as little drama as possible.  And sometimes that means that things won’t happen on schedule, because we’re going to wait out whatever adverse weather condition is out there.

“ … or is the assumption that nothing they can really do has not been
  foreseen by the designers?”

Airliners today are pretty tough, but a sufficiently negligent pilot can mishandle them to the point of catastrophic failure. (Fly-by-wire gives some protections in this regard, but also allows for failure modes that are easier to catch in non-FWB aircraft — Air France 447 as an example of the latter.)  The designers known that somewhere in the aircraft’s lifespan, the flaps will be oversped, and there is ample safety margin there.  But if you go pulling 9 G’s on a full airliner, the designers can’t help you, and you are absolutely beyond any margins they gave you.
In general, the range of techniques that 99.9% of airline pilots will use won’t greatly affect the service life of an aircraft. It will be limited (typically) by pressurization cycles more than by anything else.  And that’s because the culture IS to keep things safe, and calm, and as smooth and as low-drama as possible.
Did I mention that “Flight” really is about an alternate universe mostly unrelated to our own?

Haha... yes, you did. And I assumed it was: when Hollywood has a chance to take liberties with the facts, even if the plain facts are more interesting and would make for a better movie, it will always opt for juvenile comic-book nonsense.  It's just that the concept of a "macho" manoeuvre to avoid "bad air" was one that intrigued me... I've now got a couple of great answers.

I am a private pilot and fly small single engine airplanes like Cessna 172.
Cessna doesn't have any self correcting mechanisms, it just does what you command it to do by controls.
That's why you can put the structure under undue stress by not trimming or not distributing your passengers in a balanced way on the seats.
You can also help the plane's frame last longer by avoiding flying behind or ahead of power curve, meaning you don't want to hang from the propeller or fly too rich on high power.
I know the big planes have redundant systems of automatic correction, not small airplanes though. They can't afford extra cost nor weight.

Not sure that most of the things you list put stress on the airframe. Trimming means that you don't hold pressure to keep the elevator where you want it, but it's there either from your force or aerodynamic force from the tab. W&B is important, but unless it leads to a crash, the "balance" part isn't about airframe life. Likewise flying behind the power curve -- bad, but for different reasons. Agree with too rich/lean -- that affects engine life. Hard landings & too many G's -- those would affect airframe life.

If you fly with all the weight on one side the frame acts as in a cantilever beam, in that case if you're flying in turbulence the stresses magnify. As for the benfit of trimming, when you use the yoke you apply force to the shaft at the base of elevator with large mechanical leverage and stresses, but trim tab is at the end with most effective impact.  If you fly uncoordinated, you correct by counter rudder. Which is undue stress.  I use an iPad for navigation which on stormy day's gets bumped around the cockpit, hence many scratches on it. It is not to expose the plane to unnecessary loads.


text:
Although 2 RVR device symbols are given in the airport planview, there are 3 RVRs (TDZ,MID,RO) in the takeoff limits section. How is this possible?
Although 2 RVR device symbols are given in the airport planview, it is written in the takeoff minimums section that all 3 RVR values (TDZ, Mid, Rollout) must be provided for the departure limits. MID RVR is not provided in planview. Is it because it is forgotten or is it because the RVR devices we call TDZ, MID, RO have different meanings? Or can a single transmissometer measure the RVR value in all areas (TDZ, MID, RO)? I couldn't understand the situation.

source: Stack Exchange

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text:
Why is there no Maltese Cross in this non-precision approach's profile view which has a FAF?
I am wondering why this chart does not show the FAF with a maltese cross as it is used in non-precision approaches to depict FAF.

Related: https://aviation.stackexchange.com/q/75458/567

Turkey does not indicate the FAF on their charts, so Jeppesen is not going to add one to their format. There’s nothing more to it than that.

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text:
What exactly is the difference between HIALS and HIALS-II lighting systems?
What exactly is the difference between HIALS and HIALS-II lighting systems? The symbols at the beginning of the runways are very different and I cannot classify them in a particular way. But in general, for most of them, either the HIALS or the HIALS-II header is used. What is the main difference between them?


text:
Which transmissometer measures the RVR value specified in the takeoff limits section? TDZ? MID? Or Rollout?
Which transmissometer measures the RVR value specified in the takeoff limits section? TDZ? MID? Or Rollout (RO)? If there are 3 transmissometers for the runway at an airport, which transmissometer measures the RVR values specified as in the example given below? Or is it the average of all? (TDZ, MID, Rollout).

Apart from averaging them, one could also conceivably take the minimum RVR of the three (which would IMHO make the most sense, in that you might need the entire runway length in an RTO and having any part of the rwy covered in fog would be unsafe).

This seems to be the value reported by ATC, which itself can be determined according to criteria explained in JO 7110.65 section 8, in particular: "When two or more RVR systems serve the runway in use, report the indicated values for the different systems in terms of touchdown, mid, and rollout as appropriate"


text:
What exactly is the difference between "to","on" and "via" in the missed approach icons section of Jeppesen charts?
What exactly is the difference between "to", "on" and "via" in the Missed approach icons section of Jeppesen charts? Sometimes "on" is used and sometimes "to" is used. As for the "via", I have no idea. I know the meanings of the words, but I guess I can't understand why they are used differently because English is not my mother tongue.

It might help to also see the corresponding missed approach description texts here.

Yes, I tried to find it too, but unfortunately I couldn't find it.

You are absolutely right sir, I am uploading the charts of all 3 samples now.

Top one:
"TO" means after climbing to 3000 ft on the missed approach track, then proceed to the VOR, the missed approach fix, and pick up the 051ᵒ radial outbound, which will almost certainly has a hold on that radial.
Middle one:
Climb to 2000 while flying ALONG the 044ᵒ radial of the CRL VOR. "ON" means you have to proceed along that particular track to maintain obstacle clearance.
Bottom one:
Go from TZK to ITZK while flying along the 111ᵒ radial of TZK while between those two waypoints, but how you get to TZK is up to you. "VIA" refers to a routing between specific waypoints as listed, where you just fly to the first one on your own using the most logical and direct routing.
You could say that the VIA instruction combines the TO instruction (find your way to the 1st waypoint) and the ON instruction (fly between waypoints on a specific track) into a single instruction.
In any case, the detailed instructions are in the MISSED APPROACH block near the top of the approach plate. Those blocks you are referencing are included below the vertical profile of the approach and are shorthand at-a-glance reminders of the key data of the missed approach.

Could you please share your source explaining this situation, sir?

It's just an english interpretation from somebody with an instrument rating. The missed approach block near the top of the approach plate explains it in plain english.

Yes, I understand, but after reviewing the charts, I think your definitions of "to" and "on" need to be swapped.

If you look at the chart I just added, according to your definition, the icons should be "to", not "on".  @John K

After reviewing the charts you posted I agree John's answer is spot on.  The differences in meaning between the "on" and "via" is negligible, and doesn't alter how you would fly the procedure.

Unfortunately, I do not agree. According to the charts, explanations and definitions were not enough for me. I don't understand the obvious difference. But I will ignore this part because it is a very unnecessary detail.

What does your instructor say?

What specific part of my comment, or John’s answer do you disagree with?  Do you think it makes a difference in how you would fly the missed approach?  If I were giving you directions to the muffin store and I said “follow Drury Lane…” or “go along…” or “proceed via… or “drive down…” does my choice of words affect how you get there?  I agree that standardized terminology is a good idea to reduce possible confusion, but this really isn’t one of those cases.

Not trying to argue here, you did acknowledge “it is a very unnecessary detail”, (which I agree with) I just feel incomplete if I can’t help someone understand something…


text:
Why don't the Altitude-DME values in the approach profile match the Groundspeed-FPM values in the conversion table?
Why don't the Altitude-DME values in the approach profile match the Groundspeed-FPM values in the conversion table?

When the calculation is made with the values given in the conversion table, the altitude values in the profile view are significantly different. To give an example from the picture, we see a profile descending from 2000 feet to 900 feet at an angle of 3 degrees. Assuming we descend at 70 knots, the vertical velocity we need to maintain has to be 372 fpm. We fly the distance of 3.4 DME between waypoints at a speed of 70 knots in 2.9142857 minutes. In 2.9142857 minutes, at 372 fpm, we would descend to 2.9142857*372=1084.1142804 feet. Although the altitude difference is 2000'-900'=1100', we calculated the altitude value to be descended as 1084'. Where does the difference of 1100'-1084'=16 feet come from?
Also, you can reach another question I asked very similar to this question from this link: Why are the altitudes and distances in the profile view different when calculated with the fpm values in the conversion table on Jeppesen charts?

Have you ever seen a DME display show hundredths of a NM?
To make the math work correctly, you will need to descend at 3.4498297885 NM on the DME.
$$
\frac{2000-900}{372} X \frac{70}{60} = 3.4498207885
$$
In both of your questions, you are assuming that we are supposed to descend exactly at 3.4NM but in reality there is an assumed error due to capability of the receiver only showing tenths of a NM.
Is it better to reach 900' MSL before the MAP or after when you start to descend at 3.5NM.

Wow, I never thought of it that way. What you say seems logical, but shouldn't the fpm value be given according to the DME value? So I mean why isn't fpm information given according to 3.4 DME? Why should the 3.4498207885 DME point on the approach path be chosen deliberately and given fpm over that point according to the altitude-DME information? Shouldn't the selected point be 3.4 DME and the appropriate fpm value should be given in the table?...

...The answer to this question would be "maintaining the 3-degree approach path". But I don't understand why the logic of what I wrote doesn't fit the situation in the other question.

I find the original question and your follow-up questions quite fascinating.  There is theory and then there is the art of executing that theory.  You are missing the art portion of the equation.  Very few pilots will start their descent exactly at 3.4 NM on the DME.  It might be 3.35 or 3.45 or earlier or later or somewhere in between.  That is the art.  The idea of these descent rate table is to get you close enough to where you should be to execute the approach and landing successfully.  No one can also maintain the exact FPM listed on the table.  It is impossible.  Pilot executes the art


text:
Does the fact that the TDZ is not written for runway 22 means there are touchdown zone lights only for runway 04?
Does the fact that the TDZ is not written for runway 22 means there are touchdown zone lights only for runway 04?

According to the Jeppensen Airport Chart Legend (p. 3) all operational runway lighting are listed.
So I assume RWY 22 has no, at least active, TDZ lighting.


text:
Why are the altitudes and distances in the profile view different when calculated with the fpm values in the conversion table on Jeppesen charts?
Why are the altitudes and distances in the profile view different when calculated with the fpm values in the conversion table on Jeppesen charts? To put it more simply, I find the distance between points according to the speed-fpm table, in how many minutes I will fly. I multiply the minutes I find by the fpm value in the conversion table. But I get values lower than the altitude difference between points and these values may vary in different calculations. To give an example from the image, an airplane flying at 90 knots will fly 3 DME in 2 minutes. If it descends at 478 fpm, equivalent to 90 knots on the conversion chart, it descends 956 feet in 2 minutes (2x478=956). The descent in the 3 DME should be 987 feet (3000-2013=987) in the profile view, while the descent calculations given in the conversion table should be 956 feet. Where did the 31 feet in between go? Or is there an intentional reason for this? I would be glad if you help. The image is taken from page 11-1 of "LTBU" code Corlu Ataturk airport Jeppesen chart.

I think the problem may be an incorrect assumption about the 3,000'.  The 2013' and 740' heights are precise surveyed heights at the respective DME distances.  But the chart very specifically avoids calling out a specific height at D7.6.  The assumption is that you'll be level at 3,000', and that altitude intercepts the GS at a distance that equals D7.6, rounded to the nearest 10th.  If they intended to imply the precise altitude at D7.6 was exactly 3,000, they would have marked it accordingly.  Your 31 feet of error represents intercepting the GS about 4 or so seconds after passing D7.6.

If your approach was correct, my calculations for the distance between 2013 and 740 feet should have been accurate. But unfortunately, there is a difference of 30.2 feet again. Considering that we descend at 90 knots ground speed, according to the conversion table, we will fly the distance of 3.9 DME in 2.6 minutes (3.9/90 * 60 = 2.6). If we descend at 478 fpm in 2.6 minutes, we descend 1242.8 feet (2.6*478=1242.8). This means that we will be at an altitude of 2013-1242.8=770.2 feet. But we should have been at 740 feet. The difference is 770.2-740=30.2 feet! @MaxR

Moreover, if you hold a GS of 3.00° from 2013' to 3000', it will require you a distance of 3.10 NM to do so, and not 3.00. The chart probably accounts for some inaccuracies.

So, I decided to just start from scratch and build a model that started at the TDZ and worked back out.  I wanted to determine what would happen if the DME antenna was not precisely collocated with the Glide Slope antenna.  I wanted to take into account the slant-range error endemic to DME as well.
As I tinkered with the model, what I stumbled upon is that when I input 3.00° GS, I got the kinds of errors you were describing.  But when I solved for minimum error, guess where I ended up?  At 3.09° GS, the slope that was actually published on the plate as the non-precision LOC GS.
Here's the data.  Note that I used the DME slant range and not the horizontal ground distance, in my altitude computations.  Also, I used the plate's 508' elevation for the baseline, whereas the airport charted elevation is 570'.
Table 1 - 3.00° GS

Degrees
DME
DME Dist
Horiz Dist
Alt AGL
Alt MSL
Expected
Height Error

NM
Feet
Feet
Feet
Feet
Ft MSL
Feet

3.00
-
-
-
-
508.00

3.00
0.7
4,253.34
4,247.51
222.60
730.60
740
9.40

3.00
1.1
6,683.82
6,674.66
349.80
857.80

3.00
4.6
27,950.52
27,912.21
1,462.82
1,970.82
2,013
42.18

3.00
7.6
46,179.12
46,115.83
2,416.83
2,924.83
3,000
75.17

Table 2 - 3.09° GS

Degrees
DME
DME
Horiz
Alt AGL
Alt MSL
Expected
Height Error

NM
Feet
Feet
Feet
Feet
Ft MSL
Feet

3.09
-
-
-
-
508.00

3.09
0.7
4,253.34
4,247.16
229.27
737.27
740
2.73

3.09
1.1
6,683.82
6,674.10
360.29
868.29

3.09
4.6
27,950.52
27,909.88
1,506.66
2,014.66
2,013
(1.66)

3.09
7.6
46,179.12
46,111.98
2,489.26
2,997.26
3,000
2.74

I post this as an "answer" because I needed the space and table capability that the answer block provides...  But I acknowledge that this doesn't answer the question of "why?"

+1, this actually makes perfect sense: the exact altitudes are only relevant for the LOC approach (with 3.09° slope). On the ILS you don't care about exact altitude, you just follow the GS (cross-checking altitude is still important, but not at this accuracy).

Your approach to the question and your effort are very good. However, despite all these calculations, I still do not understand the 2-3 feet margin of error, even if it is small. I think the most summary conclusion that can be drawn from these calculations is this: DME-Altitude values seen in the profile view section of the approach represent the LOC approach, not the GS approach. By the way, you mistyped 505 where you wrote "plate's 505' elevation", could you please correct it to 508'? Thanks for everything.

@pilot162 As I mentioned in my first comment, I don't see the 3,000' altitude as being "authoritative" whereas I agree the 740 and 2013 should be spot-on.  So when I focus on those two, I can arrive at a zero-error solution by making (a) tiny adjustments to the ILS GS angle, and then (b) moving the location of the DME antenna some number of feet forward or aft of the GS antenna.  The GS slope through both points is 3.0794°, and the DME antenna would be about 65 feet from the ILS antenna to create a zero-error result, with 7 feet of error at intercept.

@pilot162 I'm still tending towards Bianfable's thoughts as well, that the shown heights are for the LOC approach and are not intended to make any exact statement for the ILS.  In fact, there could be small distance differences between the designated touchdown point, used in calculating the LAC non-precision descent, and where the ILS antenna actually ended up being located.  And remember, they are rounding DME distances to +/-0.05nm (300'), altitudes to +/-0.5 feet, and glideslopes to +/-0.005°.  There's some play in the solution that we just have to accept as margin of error.  That's a D

I got it, but I think Jeppesen should have taken all this into account because it causes a lot of confusion. By the way, I have another question to ask: the expected MSL corresponding to 1.1 DME is 850', which is a huge difference of 18.29 feet at 3.09° GS approach. If you ask where 850' feet came from, 850' DA/MDA is given for the missed approach point icon in the landing minimums section. I am adding the new image with the edit. Unfortunately, another problem has arisen.

I'm also totally confused about the VOR chart in the question at this link because everything is incompatible: https://aviation.stackexchange.com/q/97678/65367

Hint: You need to take the curvature of the earth into account if you want to improve the altitude accuracy. As far as I can see you have used a flat earth model.


text:
Although this approach is suitable for straight-in landing minimums in every sense, why are circle-to-land minimums given?
Although this approach is suitable for straight-in landing in every sense, why are circle-to-land minimums given? There are no obstructions, the gradient in the descent path is not steep and the approach course is the same as the runway course (044°). How and why are the minimum values on such VOR charts A, B, and C always classified as "circle-to-land"? Why can't it be classified as a straight-in landing? I thought it might be because there is no DME, but there are also charts of airports that use DME with VOR A. There are other charts that use straight-in landing minimums for this airport, yes I know, but I do not believe that charts were produced just to be able to call the minimums of such an approach as circle-to-land minimums.


text:
How can I find the type of CRL VOR at LTBU Corlu Ataturk airport? (Terminal,Low,High)
How can I find the type of CRL VOR at LTBU Corlu Ataturk airport? (Terminal, Low, High) Although there are reference documents for the FAA, I could not find a document for ICAO with the types of VOR stations on the Jeppesen charts. As an example, I am asking about CRL VOR at LTBU Corlu Ataturk airport.

In general, you can find such information in the AIP (Aeronautical Information Publication) of the country that operates the radio navigation aid. In section GEN 2.5 you will find a list of radio navigation aids. In section ENR 4.1 you will find more details for the en-route radio navigation aids.
In this case, you can find the overview list in the Turkish AIP (on the left select AIP > GEN > GEN2 > GEN 2.5):

(cropped from PDF)
The purpose can be E for en-route, A for aerodrome and AE for dual purpose. The CORLU VOR is therefore used for both en-route navigation and for the aerodrome (LTBU). As far as I know, there is no general distinction between low or high VORs, only en-route and terminal/aerodrome (the low and high distinction might be an American thing, see also this question).
More details are given in ENR 4.1, but unfortunately the Turkish AIP does not allow access to the ENR section without registration and payment (same for the AD section where details for each aerodrome can be found). Here is an example from the Austrian eAIP for detailed VOR information:

(ENR 4.1 RADIO NAVIGATION AIDS - EN-ROUTE)
The last column shows the coverage information for the VOR, which would make this something in between a low and high altitude VOR in the US (based on the definitions in this article).

Thanks for the answer, but the AIP section doesn't specifically mention terminal, low or high, right? Because I couldn't find it in the table on the AIP page that I added with the edit. I think we just evaluate the range of coverage in the remarks section and decide whether it is terminal, low or high accordingly, right?...

...According to this situation, is it possible to say "HIGH VOR" because 75 NM coverage is more than 40 NM? Or we are not sure that it is high, but should we say "between a low and high altitude VOR" as in the example you gave from Austrian eAIP because it is more than low VOR's range? @Bianfable

@pilot162 A terminal VOR would correspond to an A entry in the purpose (aerodrome only). For E or AE, the VOR is also used en-route, but AFAIK there is no definition for low or high VOR outside the US. The 75NM coverage is not enough for a high altitude VOR in the US (requires up to 130NM for some altitudes, see linked article). So I would call CRL something in between.

Yes, as you said, I saw the range values that should be at different altitudes. For this reason, as you stated, it would be the most logical approach to say that it is between low and high. Thank you very much for your answer and reply!


text:
What values will I use for circle-to-land in categories A and B? RVR 1800m or RVR 2200m?
What values will I use for circle-to-land in categories A and B? RVR 1800m or RVR 2200m? And if I am using them, why are the visibility values such as 1500m-1600m determined?

Before you can do a circling approach, you must do either a either CDFA straight in, or a non-CDFA approach to runway 22, and then circle to land on a different runway.
The circling minimum are dependant on which straight-in approach you conduct, and also dependant on the availability of ALS lighting:

Appr. CAT
CDFA
ALS
MDA
Vis. / RVR

A
yes

1100'
1500m

B
yes

1100'
1600m

A
no
yes
1100'
1800m

B
no
yes
1100'
1800m

A
no
no
1100'
2200m

B
no
no
1100'
2200m

Thank you for the tabular reply, captain. I missed that I had to do a straight-in-landing approach first to be able to circle-to-land. But the phrase "approach lights have no effect on circling minimums" in the Jeppesen Manual confuses me. Does "minimums" here represent 1100 feet of MDA? I would be very happy if you reply. (I've attached the image of the expression in Jeppesen to the question.)

That confuses me as well. “Minimums” includes ceiling and visibility. Maybe someone else here might know the answer.

I think what is meant here is the following: Whether there is ALS in direct approach or not affects the RVR or visibility value, but there is no such distinction for circle-to-land. When we look at the circle-to-land section, we see that there is no separate MDA for lighting. That's how I interpreted it, captain, what do you think?

I understand the 1st note given as follows: Since we will make a straight-in landing approach before making a circle-to-land, we also need to take into account the lighting systems that affect the straight-in landing minimum values. However, this is a situation that we will only evaluate when the circle-to-land visibility or RVR value is lower than the straight-in landing values. It would be my pleasure if you approve my interpretation, captain.


text:
What are the meanings of the numbers "4500" written under the VOR and NDB boxes? (MHA?) (Recommended crossing altitude?)
Does it directly mean the minimum altitude for holdings on VOR or NDB or can it be interpreted in another way? Because MHA 4500 information for the holding is given on the right side. This picture is taken from LTBR airport's ILS Z or LOC Z Rwy 25R Jeppesen chart with page number 11-1.

Are you saying this is not in the Jeppesen documentation?

I didn't mention anything like that in the question. I'm also looking at the Jeppesen manual, but I couldn't see a one-to-one correspondence and wanted to ask this question because I felt the need to get approval for an equivalent explanation.

What’s the date on that chart?

27 May 2022 is the revision date of the chart.

Could you post the entire chart rather than just a crop of the bit you're asking about

I'm taking a screenshot because the image quality is degraded in the full screen and the important part is too small. Also, if I can, I will share the link of the high resolution version of the page, but I haven't figured out how to do it yet, sorry.

This number is a Crossing Altitude for the initial approach course / racetrack.

Altitude/FL indicated by state source as recommended will be charted without over-bar and under-bars.

The MHA, on the other hand, is part of the missed approach procedure.

Does it always represent the intermediate approach course?

@pilot162 Are you asking about something other than the ILS Z as charted?  It is certainly possible to have other procedures or airways associated with the VOR, but the Crossing Altitude for the ILS Z procedure wouldn't be relevant to other uses.

Adjusted to initial course, not intermediate.

Let me summarize if I got it right. "4500" means the recommended VOR crossing altitude for performing the ILS procedure. Am I right?

@pilot162 Yes it is as simple as that.  If there is any lingering question about the procedure, it would be necessary to use the government chart or text rather than Jeppessen.


text:
What does "Except" mean in this ATC request?
I guess ATC wants the pilot to leave FL 280 for heavy traffic approaching from behind. But since I'm not sure, I wanted to ask. Also in the second quote from pilot, except should be expect, right?

This is a pretty common mistake people make in English, I won't mention any bias I have over which group ;)

Ahahaha, I can guess this specific group :D

It would be interesting to find the source of the information; also text would be preferable to images.

It is a typo. That is supposed to say EXPECT FLIGHT LEVEL 280 IN 10 MINUTES.
This means Atlasjet 123 is not yet cleared to the new altitude of FL280, but they can expect this clearance in 10 minutes. The reason the controller is not clearing them yet is a faster 747 behind, which would result in a conflict at the moment. Once that 747 has passed (in about 10 minutes), they will get cleared to FL280.

The second quote should also say EXPECT. They want to know for which runway they should prepare the approach.


text:
Is there a certain minimum temperature we need to turn on pitot heat on light trainer aircraft (eg DA40NG)?
Is there a certain minimum temperature we need to turn on pitot heat on light trainers (eg DA40NG)?
In the AFM and checklist documents for the DA40NG, information is given that it should only be turned on when you enter unconditional icing conditions. What I'm wondering is, is there a certain minimum temperature value? For example, we are not in cloud conditions, the weather is sunny and there is no weather phenomenon, but the air temperature is low. For example, is the degree value we need to turn on the pitot heat 10°C, 5°C or 3°C? When it is 0°C, I think it is necessary to open it because it is already freezing.

The AFM you've posted says to turn on pitot heat in icing conditions. It seems you misunderstand what icing conditions are.
You will not get airframe icing simply because the temperature is 0 degrees. The other requirement is that there needs to be visible moisture, such as clouds or rain.
When I am flying in VMC, I don't use pitot heat at all, because the likelihood of the pitot icing over is close to zero. If IMC, I turn it on at about +2.
Note that this is different from carburettor icing/heat. The carburettor can be affected by icing even in quite warm conditions, depending on the humidity level.

Diid you mean VMC/IMC? Because you can fly IFR on a gin-clear day

@Jamiec I wrote VFR/IFR because for a moment my brain forgot the terms VMC/IMC existed and are a much easier way of explaining what I meant :)

There is no limitation listed in the operating limitations, NP, EP, or airplane systems sections of the DA-40NG POH requiring you to use pitot heat only when entering inadvertent icing conditions.  You may use pitot heat anytime that you wish, but in an emergency situation of inadvertent flight into icing conditions, the pitot hear MUST be switched on.
One possible scenario where pitot heat may not be utilized is a departure into non-icing conditions from an airport with a high density altitude, since the power being drawn from the alternator to provide pitot heat is reducing the airplane's already limited ability to climb.  This should not be a problem with a DA-40NG as the turbodiesel engine has a critical altitude somewhere around a density altitude of 13,000 or so feet.  So if you're planning a departure from Lake County Airport in Leadville CO mid August at noon, maybe.  But the scenario is pretty absurd and there's a lot more on your plate that just pitot heat.

If you are a pilot, what is your personal opinion? At what degree would you turn on the pitot heat in the optimistic weather conditions I wrote above? 5°C, 3°C, 1°C, 0°C or minus degrees?

Well. let me ask you:  In what conditions and temperature ranges are you likely to encounter structural icing?

If the conditions I mentioned above are present (For example, we are not in cloud conditions, the weather is sunny and there is no weather phenomenon), it is normal to expect icing at 0°C and around. But my question is, is there any limit to this? For example, to turn on the pitot heat, do you wait for 0°C or turn it on at 1°C?

@pilot162 That is incorrect. With no weather, you don't expect icing at any temperature. Structural icing requires both freezing temperatures and the presence of liquid water (i.e. clouds or rain).

Technically clear air icing is possible, but it's by no means normal. It requires a combination of high humidity, outside air temperature just barely below freezing, and dew point just barely below OAT.

As you stated here, what I said is not wrong. Of course, moisture, that is, liquid water, is necessary for icing. The conditions I have stated above do not mean that I ignore these requirements. You already said that a clear icing situation may occur. Considering this, it should not be too difficult to say that under the following conditions (For example, we are not in cloud conditions, the weather is sunny and there is no weather phenomenon), icing may occur, but at what degree the precautions should be taken?

You can also comment on the humidity in the air, but you must have equipment that can represent it numerically and an operational limit. @Chris

@pilot162 It is certainly not normal to expect icing, regardless of temperature, in clear weather. Clear air icing is exceptionally rare because it requires very specific conditions. You don't need to turn on pitot heat, regardless of temperature, unless there is visible moisture or you actually notice ice accumulating.


text:
Is it possible to perform a descent like the picture below which I share?
In the picture, after crossing the VOR fix aircraft does not complete a parallel holding and directly descent on the other side of the racetrack outbound track. In my opinion with Jeppesen General Airway Manual, after crossing the CRL VOR, pilot should fly 1-minute on the inbound course with outbound heading and then turn right to intercept inbound course to VOR. After the completion of this holding, pilot can turn left to fly racetrack on outbound heading, right? It's clear that the descent in the picture makes the job easier, but I don't think this is possible procedurally. Because, according to the point I underlined in the Jeppesen Airway Manual, it is necessary to intercept inbound course first to make a parallel entry to the racetrack descent ? I would be grateful if you could clarify this issue.

Can you confirm that the green line appears in the illustration in the Jeppesen manual you quoted?

Sorry but it is not. The approach on the picture above is from my flight school's training manual. So, I thought that maybe the instructor draw that approach line (green) for making it easier to approach, although it is not procedural.

You are saying it isn't procedural, but I'm still not sure why you believe that is the case.  Given what I added to my answer below, why do you think that the green line is not correct?

I guess I can't convey my problem correctly because my English is not good or I can't understand what you are saying, please excuse me. The reason is that why I think that the green line is not correct : The approach chart wants us a to apply a "racetrack" not a reversal approach like "procedure turn" or "baseturn". But in the picture, green aproach is kinda like a 80-260 degree turn and it is a reversal approach. Also I can mention that the green appproach line is approximately on the opposite direction of final approach course. In my opinion, first I should apply parallel entry to...

... holding and than I should commence my descent with exactly same line on the chart which is a outbound descent part of racetrack approach (blue line). If the other  approach (green line) is completely normal, I guess I should accept it can be apply too without any concern like obstacles or traffic issues. At the end of this conversation, I have to make myself accept that this approach is normal.

By the way, thank you for your time, sir. I am grateful.

You are welcome.  If the goal is to become established on the outbound leg of the long racetrack as efficiently as possible, a tear drop entry would work best.  But from that North sector, the standard rules of holding entry apply.  Your blue line just doesn't match anything that is taught, and is inefficient.  There is no compelling reason to not follow the green line, either in writing or common sense.  I believe you are overthinking this.

If your interpretation was correct, I would expect clear language like: "crossing the fix from the North, enter holding pattern via parallel entry.  Once established in holding, begin descent on the outbound leg to 10 DME."

Oh my god, this is exactly what I want to point out. Sorry for my confusing English.

Once you have completed the outbound leg, turned right and intercepted the inbound course, your parallel entry is complete.  If you cross the fix for the second time you would turn left and hold as published.  You are established at that point.
The only thing paragraph "b" is saying is that you need to intercept the inbound course, just as you have drawn it.  They don't want you to just make a right turn and proceed direct, you need to get over and track the inbound course.
ADDENDUM (Thanks for the clarification...)
Remember, the point of this procedure is not to enter the racetrack holding pattern as expeditiously as possible, it is to reverse course and allow you enough straightaway to intercept and fly the localizer/ILS approach.
If you had been issued holding instructions it would not be a problem to shorten your outbound leg and fly the blue line, (especially presuming the inside racetrack is the holding pattern) but you wouldn't want to do that if you plan to fly the approach.
In fact, paragraph "b" is explicitly telling you NOT to do this!  "Shall not return directly to the facility without first intercepting the inbound track" means you need to extend your outbound leg far enough so that when you reverse course you can intercept and fly the inbound course.  Your blue line does not do that, it actually "returns directly to the facility" WITHOUT intercepting the inbound track.  (well, you might have drawn a tiny little bit of straightaway showing an intercept, but hopefully you get my point...)
Does that help?

I was just asking if this approach is possible procedurally. Because although the plane entered parallel to the hold, it started to descend directly on the opposite side of the racetrack leg without intercepting inbound. By the meaning of the intercepting here, I do not mean to establish the final approach course. What I mean by the meaning of intercepting was to fly outbound heading on the inbound course and than flying directly to VOR for applying the complete procedure of parallel entrance for holding.

You are not expected to intercept the inbound course and track it outbound.  You go parallel to it.  So again, maybe I'm not totally clear what your confusion is, or what you mean by "possible procedurally"...

First of all, I would like to thank you for your comments and help. For easier understanding, I have shown my idea by drawing it on the chart with a blue line. In my opinion, wouldn't the holding and racetrack have to be flown on the blue colored route because of the procedure? That's all I want to ask.


text:
Are the runway directions given in the table relative to magnetic north or true north? (True or Magnetic?)
Are the runway directions given in the table relative to magnetic north or true north? (True or Magnetic?) How can I understand this? Is there a specific case for charts?

Actually no, what I want to ask is are the degrees in the DIRECTION section marked with yellow color magnetic or true? But I guess from your answer these degrees are magnetic, right?

They are most liikely magnetic as the @RTO answer indicated.  However, Jeppesen 10-9 chart for LTPA shows runway magnetic headings of 50° and 230° respectively.

Lido by Lufthansa Systems shows 048°52' and 228°63' with a 5°E magnetic variation.

@mins: According to the information I got from the site at this link (https://metar-taf.com/airport/LTAF-adana-sakirpasa-airport), the direction was determined according to "True North" and the direction of the runway was shared as "True Heading". To be sure, I compared the directions of different airport charts with the data on this site. All direction data match "True Heading".

I think you don't need to blame yourself because what you said is not wrong. Of course, the runway numbers are given by rounding to the nearest number of the magnetic headings of the runways, and as the magnetic inclination changes, the runway numbers also change. But that's not what I was discussing here, I already knew this information. All I wanted to know was whether the "DIRECTION" information on the AIP aerodrome chart was "True" or "Magnetic".

The answer is these bearings are referenced to true north as indicated in the official AIP for Turkey:

However I don't understand why this reference to true north is not explicitly mentioned in the question chart, explanations are welcome.
The general recommendation from ICAO related to runway information is provided in Annex 4 to the Chicago convention:

CHAPTER 13. AERODROME/HELIPORT CHART — ICAO
13.6 Aerodrome/heliport data
13.6.1 This chart shall show:
d) all runways including those under construction with designation number, length and width to the nearest metre, bearing strength, displaced thresholds, stopways, clearways, runway directions to the nearest degree magnetic, type of surface and runway markings;

Annexes are only recommendations to States members, however when a State doesn't follow the recommendations it must provide a description of the deviations in the section GEN 1.7 of the AIP. In this case the deviations related to §13.6.1 are:

13.6.1.g TWY markings are not shown
13.6.1.i TWY centerline points and aircraft stands are not
shown

No deviation for 13.6.1.d, so the runway bearings should be referenced to magnetic north. This is not a problem when reading documents where the reference is explicite (e.g. in the table above), but the aerodrome chart in your question has no warning.

A last point about bearings.
Before modern navigation instruments, in particular before GNSS, the compass was the reference. Today the magnetic reference creates many problems linked to how magnetic bearings are determined and used:

First a GNSS (or INS, or sensor-fusion) bearing is determined, it is true by nature as the coordinates reference system used for position determination has an ellipsoid aligned with Earth rotation axis (WGS-84).

Then tables are used to convert it to a magnetic equivalent because magnetic bearing is the legal reference for navigation, for crews and controllers.

While avionics silently uses the true bearing which is more simple, for all its calculation, all bearings displayed to the crew, or entered by the crew, will be magnetic.

The conversion tables are derived from the World Magnetic Model. All avionics units use this model, but different units may use different versions, and updates may be slow or inexistent. In addition units may use different algorithms and get results not matching or not matching with maps/charts.

So there is a project to stop using the magnetic reference and switch to a legal true north. Canada is driving this project for ICAO. Canada is indeed interested more than other because in polar regions, the magnetic declination varies a lot with position and also in time. So for these regions, and only for them, the legal reference is true north. Canada, among other, must live with two legal systems and make them more or less compatible.
You may read more:

ICAO: Moving from Magnetic to a True North reference system in aviation
Nav Canada: MAGNETIC TO TRUE NORTH - Change by 2030


text:
Why do all trend vectors in the G1000 on airplanes indicate the status 6 seconds later? Why 6? Why not 5 or 10?
Why do all trend vectors in the G1000 on airplanes indicate the status 6 seconds later? Why 6? Why not 5 or 10? The fact that the trend vector shows after 6 seconds allows us to turn 3 degrees per second in standard turns. Anyway, why 6 seconds for speed and altitude? I've also read that on heavy aircraft like the A320, this trend vector shows 10 seconds ahead. Is it related to the plane size?

Speculation: A standard rate turn is 3 degrees/second. Maybe it's convenient to have the trend vector be a multiple of that value

More speculation: 6 seconds is also a nice fraction of 1 minute (one tenth)  making it easy to extrapolate out to, say, feet per minute.

The standard turn rate reference mark is located 18 degrees to the right and left of the luber line from the calculation of 6x3=18 degrees. If the trend vector was 5 seconds, it would be 5x3=15 degrees to the right and left. So it's not really about the standard turn speed of 3 degrees/second. @60levelchange

If we think on a fraction basis, the numbers 5 and 10 are also very good numbers for 60 seconds (1 minute), and they can divide 60 seconds exactly. I don't think the situation is related to that either. @TypeIA

@pilot162 Most people can mentally multiply/divide by 10 much easier than by 12 or 6, for the obvious reason.

Adding to the confusion: airspeed trend vector on this system is a ten second prediction.  So why is six seconds preferred in one place and not another?

All trend vectors in the G1000 on airplanes indicate the status 6 seconds later. The fact that the trend vector shows after 6 seconds allows us to turn 3 degrees per second in standard turns.

It's a graphical space reason.
Vertical Speed
The altitude tape shows the current altitude approx. $\pm 300$ ft. Therefore, the maximum trend you can show is $\pm 300$ ft in $x$ seconds, thus $300/x$ is the maximum allowed vertical speed so that the trend bar fits the altitude tape. What is the maximum vertical speed which must considered acceptable? $3000$ ft/min? $\pm 3000$ feet/min = $\pm 50$ feet/sec. Then, $300/x=50 \to x=6$ seconds.
If they would have pick $x=5$, then the maximum would have been $3600$ ft/min which is too much for an aircraft equipped with a G1000 (and space for trend symbol would have been wasted), while $x=10$ would lead to $1800$ ft/min which is too small. $3000$ ft/min is a reasonable choice.
Airspeed
Same reasoning for airspeed. It shows $\pm 30$ kts, then $30/6$ means $5$ kts/s, which is a reasonable maximum acceleration for a GA.
Let's look at the 737, in this case $x=10$ seconds, but the tape displays $\pm 50$ kts, thus a maximum of $5$ kts/s, identical. In the A320, also in this case $x=10$ seconds and the tape displays $\approx\pm 42$ kts, thus a maximum of $4.2$ kts/s, which is sligtly lower but it still makes sense.


text:
What is MEHT (minimum eye height over the threshold)?
What is MEHT (minimum eye height over the threshold)? I can't find the definition and how to use it.

I saw this post, but I couldn't understand how I should understand and interpret it. For the sake of clarity, I leave a picture of the part where I saw this expression.

I guess if I go below 18 feet above the threshold I won't be able to see the VASI lights. Is it simply that way?

The MEHT (Minimum Eye Height over Threshold) is composed of two values: the EWH (the eye to wheel height) plus the WTH (wheel to threshold height). Both values are for the aircraft in the approach configuration and are not the dimensions as may be measured for a parked aircraft resting on the ground. The MEHT assumes that the pilot eye would follow the lower limit of the approach corridor which is defined by angle M = B minus 2 minutes of arc. You can see this in the image below:

Source:

Precision Approach Path Indicator Harmonization with Instrument Landing System


text:
What exactly does the expression "higher straight-in minimums" describe as "higher" relative to which value?
What does the description of note 1 that I marked in the image mean? What exactly does the expression "higher straight-in minimums" describe as "higher" relative to which value? And how and when do I use RVR 1800m or RVR 2200m as the circle-to-land minimum if these are the intended values? Because there is "approach lights have no effect on circling minimums" information for the ALS system.

It's visibility.
For Cat B, your required circling vis is 1600m, UNLESS the ALS is out of service (and the non-CDFA case) - in which case you need 2000m (which is the "higher straight-in minimums").
The ALS-out mins aren't higher than the Cat C or D circling mins, so those lines don't have the "1" note, just A and B.
It makes sense that if you need "this" vis when the ALS is out of service, you don't ignore that higher requirement just because you're circling.

What you said is very logical and thank you for the answer, but what I don't understand is that the word "or" is used in the note below. So I can't use the minimum visibility value of 1600m while ALS is out? To be more descriptive, wouldn't it be logical to write "If ALS out, use the straight-in approach minimum values" in the note section?

Also, I would appreciate it if you could comment on the last image I added because there are 2 RVR values higher than 1500m and 1600m visibility: RVR 1800m and RVR 2200m. In this case, does "or higher straight-in minimums" mean the value higher than the circle-to-land value, or does it mean the highest value from the straight-in landing RVR values? (Will the RVR 1800m or RVR 2200M be used? Will the RVR 1800m or RVR 2200M be used? And under what conditions will it be used? Because there is no condition other than ALS out which is RVR 2200m.)


text:
Who legally owns the Flight Data Recorder?
Who legally owns the Flight Data Recorder after an aircrash?  Who is responsible for retrieving it and/or allowed to retrieve it?
And how is it decided who carries out the crash investigation?

I can answer the 'who is allowed to retrieve it?' part. Anyone who finds it. There is no anti-tampering built-in which would preclude anyone from 'picking it up'. I can, unfortunatly, also answer the 'how is it decided ...' part. Who ever controls the place the crash occurs, with weapons, ultimately decides, until someone else more powerful intervenes, or common sense prevails.

@CGCampbell: ICAO does have some power to persuade any country with at least a bit of sanity to follow proper investigation procedure. Territories in state of anarchy are a problem though.

Do you draw a distinction between ownership of the hardware vs the recorded data?

Who legally owns the Flight Data Recorder after an aircrash?

Whoever owned it before the crash!
I'd guess this might be the aircraft owner (e.g. an airline or a leasing company) or an aircraft operator (e.g. an airline).
Ownership is less important than the obligations imposed by the relevant regulatory authorities, and probably by international treaties and agreements, effective in the area where the FDR is located after an accident.
For relevant discussion see NTSB FDR Handbook

And how is it decided who carries out the crash investigation?

There are a complicated set of rules agreed internationally. From memory I think it goes something like this:

The government appointed body in whose territory(airspace?) the accident occurred. Or
The government appointed body in whose country the aircraft was registered.

EMSA state

5.1 The State of Occurrence shall institute an investigation into the circumstances of the accident and be
  responsible for the conduct of the investigation, but it may delegate the whole or any part of the conducting of such
  investigation to another State by mutual arrangement and consent. In any event the State of Occurrence shall use
  every means to facilitate the investigation.
5.3 When the location of the accident or the serious incident cannot definitely be established as being in the
  territory of any State, the State of Registry shall institute and conduct any necessary investigation of the accident or
  serious incident. However, it may delegate the whole or any part of the investigation to another State by mutual arrangement and consent.

Example 1

The UK Air Accidents Investigation Branch (AAIB) is part of the Department for Transport and is responsible for the investigation of civil aircraft accidents and serious incidents within the UK and its overseas territories.

Example 2

The NTSB is an independent Federal agency charged by Congress with investigating every civil aviation accident in the U.S.

Normally an air accident investigation organisation takes the lead role but co-opts experts from the airline, the manufacturer and other air-accident organisations with an interest in the incident or with special expertise. Involvement of interested parties (airline, ATC, manufacturer) obviously has to be handled very carefully to avoid detracting from the independence of the investigation.
Most investigations focus almost exclusively on determining facts and recommending actions to prevent recurrences. They generally are not mainly concerned with assigning blame, that may be the focus of a separate legal inquiry.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
Why do some nations allow the usage of hand held devices and some not throughout the landing till the take off
After going through this site I am still not clear as to why do some nations do not allow the use of hand held device's especially  cell phones for making calls or texting but for gaming or reading during take off or landing or throughout the flight.
although the difference lies in network usage but still the device is ON and still may cause disturbance to the onboard equipment like navigation or communication. Then what's the point in allowing for gaming or reading throughout the flight.
I have seen some reports that claim they don't cause disturbance and some say they do.

different companies different standards and practices.

duplicate? http://aviation.stackexchange.com/q/2021/1467

@Federico thanks for pointing out because I could not see any question when posting it from the Android mobile browser

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
Where exactly is the engine compartment, remarked in yellow?
Where exactly is the engine compartment, remarked in yellow? We know that normally the air going to the engine passes through the air filter. But when we open the alternate air valve, where does the air come from? When I examined the diagram related to this, I could not see a separate hose, pipe or transmission structure. The only thing mentioned is "from the engine compartment" and I don't know what it is. I'm also attaching the schematic found at 71-60. Our plane is DA40NG.

The engine compartment is the entire area between the firewall and the propeller, which is normally covered by the engine cowling.
The alternate air valve opens to allow engine intake air to bypass the filter, and to be drawn from the ambient air surrounding the engine itself.
This would be done in case of blockage to the air filter system due to icing or other possible failure.

They’re talking about the space inside of the engine cowling. In other words that valve can be set to feed ambient air into the turbo from an air scoop on the outside of the engine cowl.  In the case of icing or some other emergency where the engine can’t breathe normally, draw in air from the alternate air source that’s open for air inside the cowl.


text:
tail wheel landing roll out
I'm new to tail wheel and recently every time in my landing roll out the plane seems to have a tendency to to go to the right and when i try to correct it feels like the plane will tip over. Is there a reason for this? is there a way to overcome it? I am Flying a C-170B by the way with an Alaskan bush wheel tail wheel and standard tires

Welcome to the site. Are you doing three point or wheeler landings? Also, when does it go to the right, give more detail on your technique and when exactly it's going wrong.

By tip over you mean tip up on its nose, or drop a wing tip toward the ground?


text:
I believe I was misdiagnosed with ADHD when I was a small child. Can I get my private pilots licence?
I believe I was misdiagnosed with ADHD when I was a small child. I now want to get my PPL, and ive been told it might be a problem. Can I get the ADHD diagnosis removed from my medical record?
I do not have any signs of ADHD, none of my family members or friends see signs of ADHD and I can fly more than 8 hour flights on a flight simulator on VATSIM without being distracted.
I am wondering if I can get it off of my record or—if I can't—can i still get my PPL?
I live in the United states and I have not talked to an AME.

How to get a diagnosis off your medical record is outside the scope of aviation, but I would suggest you get a statement from the specialist you mentioned in your comment and ask whatever medical facility keeps your record to expunge the questionable diagnosis.  It's unlikely to be an issue if it remains, but personally I would want it gone.

Related (and no doubt useful): How does the FAA decide if a PPL applicant with ADHD can fly?

I'm somewhere on the spectrum.  Although you didn't ask, you can probably get an ADA accommodation document for your employment in the US if you have ADHD, or in my case it was under the general rubric of "stress".  This works best if you are in a organization that is sympathetic (not all are, sadly).  I realize a pilot's license (private) is not about employment, but you probably work somewhere.

Where I come from, you can change your Personal MD and not allow the transfer of your medical records (data protection reasons). This will yield a blank medical record for you. Ofcourse, that can be a problem for other reasons.

@TAndersen that doesn't work for an aviation medical. Not only can the government agencies look up records even if you've not given permission to share them (they have the legal clearance to go over your head if needed) but you're required by law to give full disclosure and a prior diagnosis, even if not part of the records of your current medical team, would fall under that. Some things of course can be different by country, but that's the same AFAIK for both EASA and FAA medicals at the very least.

Btw have you sued the doctor who misdiagnosed you?

There's a couple of things I want to get out of the way before I actually answer the question.
First, I actually do have ADHD, confirmed via multiple tests, including an EEG. It was never any obstacle for me to get my medical certificate or pilot's license. When my AME asked if I had any preexisting conditions, and I mentioned ADHD, he just waved his hand and didn't even note it down. (Of course, I'm in the US. The medical requirements might be different in other countries.)
Second, the fact that you can spend 8 hours on a flight sim is actually a point in favor of you having ADHD. Sure, "everybody knows" that ADDers can't focus on anything ever, but that's not actually true. When doing some task that actually interests us, we're actually more likely to slip into a state of hyperfocus on that task.
With all that being said, ADHD isn't something you can get, or something you can be cured of. It just is. So, if you can get a doctor to say that you don't have it, that's the same as them saying you've never had it. My advice to you is to ask your AME if it's even a problem in your country, and if so, find a neurological specialist to test you for it.

thank you i live in the us and i was formally diagnosed with ADHD but i went in to get reevaluated and the specialist is pretty amendment that i was most likely misdiagnosed when i was 8 or 9 years old

@silvertheflyguy If that's the case, then you're good to go. (Just FYI: you probably should have put that in the question. Having a specialist say you don't have it carries a lot more weight than saying that your friends don't see signs of it. There's a lot of misinformation about ADHD in the public consciousness, so how would your friends know specifically what to look for?)

Your experience is very much not in line with others I have seen online. Were you ever prescribed medication for your ADHD, and if so did you report that? That seems to be the major sticking point for a lot of cases.

@randomhead As I recall (it's been a while), we'd already established that I wasn't taking any medications for anything. Maybe that's the reason?

Just be sure to answer all the questions on the medical application truthfully and completely. When you sign it, you are attesting that it is true and complete. If you leave something out, they can claim falsification and that will get you denied or a suspension if they find out later. It may take extra review, but as others have indicated you should be good. If it does look like it will be an issue, I would suggest talking to AOPA. They have a team specifically to address medical certs.

Dear all, please keep your comments on topic, which is the question and the answer above. I understand that differences in opinions on ADHD can fuel the need for a heated debate; this is not the place. Please be kind to each other, and keep the comments focused on aviation.

Coming back to point out that your experience is NOT typical of those with ADD/ADHD. The FAA's Guide for AMEs says that ADD "Requires FAA Decision," that is, the AME should not have issued your medical themselves. You were supposed to go through psychological test batteries. As it stands your answer is very misleading to other applicants with ADHD.

In Australia, you can probably get a license.
According the aviation medical ADHD page on the website of the Australian regulator, the Civil Aviation Safety Authority:

Indicative outcomes
Unrestricted certification is possible if in full remission without medication
Favourable
ADHD diagnosed in childhood and treated with no persisting symptoms without medication for at least past 6 months
Adult ADHD not on any treatment for at least 6 months

If what you're stating in your post is accurate, it certainly sounds like you'd probably be able to get a license.
Of course, I'm just a random person on the Internet, rather than a doctor or one of CASA's regulators, so if you do decide to apply for a license here, I'd encourage you to reach out to them using their aviation medical enquiries contact form to get definitive advice.


text:
Pitch=Flight Path Angle + Angle of Attack if bank angle=0?
Question: Is the statement in the title correct?
Recently, I am taking a course about flight mechanics (click for the slides). It states that "If bank angle is null, then pitch angle = flight path angle + angle of attack" in the page 6 of slides. However, I disagree on it. I will first show an example which I plotted in Geogebra (click for the 3D Geogebra model) (screenshot is also posted below). In the example, pitch angle = 45 degree, flight path angle = 24.09 degree and angle of attack = 19.76 degree, so
$$
\text{(pitch angle)}45 \neq \text{(flight path angle)}24.09+\text{(angle of attack)}19.76
$$

Besides the above example, here is my reasoning:

Since there is no bank angle (means roll = 0, click for reference), so the symmetry plane of aircraft is vertical plane, which is perpendicular to horizontal plane
Angle of attack is defined as the angle between "projection of velocity vector in symmetry plane of aircraft" and "x_b"
flight path angle is defined as angle between velocity vector and horizontal plane
pitch angle is defined as angle between "x_b" and horizontal plane

Based on the above points, it is impossible for pitch angle = flight path angle + angle of attack. I believe if both roll = 0 and slideslip (here is yaw previously, should be slideslip, thanks to @U_flow) = 0, then it is correct that pitch = flight path angle + angle of attack.

Ah, I see: You included a sideslip angle in your Geogebra calculation, not a yaw angle. Therefore the assumption that $\theta = \gamma + \alpha$ is correct if $\phi=0$ AND $\beta=0$. I think in that sense you are correct.

I can't understand your 3D model from the screenshot, and when I try to view it in Geogebra online, I only see two rectangles, one point, and one line segment. I think it would be a good idea to include a text description of the orientation of your aircraft and its direction of travel, so that we can follow your calculations.

@MichaelHall Sorry. Question was just added.

@TannerSwett Sorry for this, but I think there maybe something wrong with your computer. My 3D model has many points, lines and labels. To provide the whole picture of the axes, this is the link of the earth axes and body axes I use in the model: flight mechanics reference frame

@U_flow Update: Agree, in my conclusion, "yaw" should be "sideslip". Thank you a lot!

You are correct, at least in theory. In order for the rule to be correct, we need to add one more criterion: that the sideslip angle is zero (or negligible).
Here is an even more extreme example. Suppose that an airplane is flying with a pitch of 89.999 degrees, a bank angle of 0 degrees, and a heading of 0 degrees (due north). It's traveling up and due east, with a flight path angle of 45 degrees. Then the angle of attack is very nearly 0, and adding the flight path angle gives approximately 45 degrees, which is quite far away from its pitch of 89.999 degrees.
(Needless to say, it would be very difficult to make an airplane actually do that.)
In practice, I think that the sideslip angle is practically always small enough that the rule has an insignificant amount of error.

Thanks for this. Agree on that if both sideslip =0 and bank=0, the conclusion is correct.

I think there's simply a typo in the last sentence of the slides: a "and $\beta$ is null" is missing where it said "If bank angle $\phi$  is null, then:".
Or it has been implicitly supposed that, being $\beta$ normally very small, for all practical purposes it has a negligible impact on that equation. But I agree that this should have been stated anyway.

Agree. Thanks for this answer.


text:
The weather balloon began to bounce less as it entered the stratosphere
We launched a weather balloon where one of the sensors was an accelerometer. The data from it show all parts of the flight (1 launch (0 m), 3 bursts of the balloon (35,800 m), 4 landing (0 M)).
We also measured the temperature, which shows that the balloon left the tropopause and entered the stratosphere at 9:20 a.m. at an altitude of 18 km (3).
What is interesting is that the data from the accelerometer shows that at that moment the balloon experienced a relatively large shock and subsequently stopped flapping as much as it did in the troposphere. What is it caused by?
The Z axis was pointing up in the direction of flight.
The balloon was launched on 17.9. 2021 from the Czech Republic.

Launch
The end of the tropopause and the beginning of the stratosphere
Balloon burst
Landing

Update: In flight photo

There is a balloon at the top, a parachute in the middle and a small round probe at the bottom. When the balloon burst, everything fell together in a big mess.

Providing an excellent confirmation of air pressure (and density) vs altitude when it fell.  Scroll down for graph.  I never knew that lifting capacity does not decrease with altitude flying an expanding balloon, but it now makes sense.  That's how manned balloons can go over 30,000 meters.

Nice data. I don't understand the plot of the temperature though: why the big drop when it bursted?

Changes in temperature are caused by how the balloon passed through different layers of the atmosphere. It's easy to see when flying up. But the temperatures are
@sophit very high there, because the probe was probably heated by the sun. On the descent, the same thing happened, but the temperatures dropped much lower because the probe was blown more by the wind and cooled down to the actual temperature that prevails in that location in the atmosphere.

I'm suspicious of the acceleration data.  Do you know why X and Y are nearly constant but non-zero?  Could it be off-axis?

@BowlOfRed Yes, I think that it is off-axis. I don't think there's any other reason why it should look like this.

The balloon really seemed to settle down once it entered the stratosphere, and had larger changes in vertical velocity before that, and after bursting.
If I may assume there was a parachute recovery, then I would like to suggest interaction with variable winds as the cause.  The balloon and its cargo were probably swinging back and forth, which, by changing drag profile, would affect the vertical velocity up and down.
The stratosphere is known to be a bit calmer, and, as the balloon approached burst, the tension on its skin may have been strong enough to better resist deformations, which would also affect its passage through the air.
What was very impressive is the constant rate of climb all the way up.
Congratulations on your flight and recovery of some very interesting information.

Thanks for the reply. I updated the questions with a photo from the flight and another description. So you think the calming is due to the stratosphere being calmer? But what is the cause of the shock before entering the stratosphere (2)? The weirdest is the one in the Z axis.

@SaturnV probably some heavy turbulence at the interface of two atmospheric layers or a down draft.  Curious how far did you have to go to recover it?

The balloon landed about 100 km from the launch site. I also noticed that the same jolt probably happened on the way down between 10:47 and 10:57.

@SaturnV the spike on the Z axis might be consistent with the balloon being pulled sideways as it ascends/descends through a wind gradient.  In that case z temporarily no longer points toward earth.  As far as you traveled in ground distance, you must have had alot of wind.  Getting a local airport METAR may be helpful for your next flight.


text:
Why do helicopters experience a brief dip in altitude during IGE marginal power takeoffs?
The scenario is this: A helicopter is hovering IGE, and executes a marginal power takeoff. What causes the dip in altitude that occurs around 10 knots during the takeoff?
Most pilots seem to describe this event as, "feeling as though the aircraft is leaving a cushion of air." Is it caused by the increase in induced flow through the rotor system, thereby briefly reducing blade alpha until reaching ETL? Thanks for your time!

There is a discussion of this phenomenon in Raymond Prouty's book Helicopter Performance, Stability and Control. Chapter 3 describes momentum methods for the physics in forward flight, including the transition from hover to forward flight in ground effect.

Above image is from the book, and illustrates what happens:

Test experience, however, shows that during transition from hover to forward flight at heights less than about half the rotor diameter, the (required) power may actually increase rather than decrease. Pilots speak of this as "running off the ground cushion."

The reversal of ground effect is due to the helicopter overrunning the ground vortex, as illustrated in Figure 3.12...As the leading edge of rotor approaches the ground vortex, the inflow is increased just as if part of the rotor were in a climb, thus increasing the power required. The recovery to a more normal inflow pattern occurs suddenly as the vortex passes under the rotor.

The book cites research conducted in the quoted text, which I have left out. In the figure the described effect happens starting at 15 knots, a function of helicopter disk loading, relative Height Above Terrain etc.

What an excellent answer! Thank you for taking the time to write it! And I'll have to check out Mr. Prouty's book!


text:
If they really wanted to, COULD they make a 100% fail-safe airplane?
With literally every single electronics device that I have bought in the last X years breaking very quickly or immediately, and being of horrible quality, this thought keep popping up in my mind:
If they really wanted to, meaning money is not an issue whatsoever, could they manufacture an air plane which is 100% fail-safe, and thus cannot possibly crash or fail to take its passengers and crew from the pre-determined points A and B?
I'm not trying to make this into a "trick" question of some kind. We are not talking about any "lab conditions" or special rules of any kind. It has to be a commercial jumbo jet, but without the issue of money and with the determination of everyone involved to actually make this indestructible and 100% fail-safe air plane.
The fuselage would be impossible to break, even if it somehow crashed. The engines (naturally, they would be four or more) would have specially designed parts made from the most durable materials that exist or can be made with our current knowledge. All kinds of safety measures and maintenance checks can be freely added since there is unlimited funding. One could even replace the entire plane with a brand new identical model for every single flight, just to further increase the likelihood that something did (somehow) wear out from the one voyage the previous plane made.
The requirement is that this plane never crashes or kills or hurts anyone, no matter how many birds come flying into every engine constantly, no matter the extreme weather, and even if all 48 onboard redundant backup-pilots die at the same time. In fact, every single passenger is a pilot.
Of course, this is a very theoretical and implausible question, but it somehow feels to me as if they could achieve a perpetual perfect score of "zero major indicents" if this madness were to be attempted. (Which it obviously never will.)
It genuinely frightens me to think about what kind of greedy people run these companies, and that I am at their cost-cutting mercy to not look out through the window and notice how the jet engines are falling apart mid-flight because they skimped on the routine inspections and some stupid little detail broke because they cannot possibly "do it properly" under these economic constraints.
I also very much wonder if private jets used by billionaires have special, much better and more expensive parts and stricter maintenance checks than what commercial jumbos have. I imagine that this must be the case, because they can afford to "buy safety".

Kind of philosophical question here. Most of the aviation incidents are human driven and/or caused by a not-foreseeable problem. Both cannot really be solved making airplanes even safer of what they already are.

But why the downvotes?

@coron - suspect because a 100% safe anything is impossible, it is still vulnerable to a dinosaur killer asteroid, heat death of universe etc. The question might be more sense if you asked how much risk is accepted in aircraft design, which is something hashed out during the 737 Max saga. The last part is a separate question, and by asking it as written you are saying the people who could answer are either incompetent or criminal so would be better with some tweaking - there is a good question in 'are business jets safer because money' but needs to be pulled into a standalone question.

The second part of your question is based on a false premise. Air travel is actually extremely safe because of strict regulation and the need for airlines to maintain a good reputation. Private jets aren't maintained any better.

@GdD "Extremely safe" until it's not.

"But why the downvotes?" that's another philosophical question  Theoretically people should first of all leave a comment on how to improve your question/answer and eventually downvote afterward  Anyway if you follow the advice of @GremlinWranger you should come up with a good question indeed.

I am voting to close because this question can only be answered with opinions.

I didn't DV because it would feel like piling on at this point, but to add to the other (accurate) speculation on why you are getting downvoted, you come across as someone with an axe to grind and/or an irrational fear of air travel.  The modern aviation industry is not perfect, no business ever is, but it is a remarkable feat of engineering that is operating at an extremely high, (and VERY safe) level.  Your question reads like a rant in favor of the impossible.  (i.e. "they could guarantee my safety 100% if only they weren't so greedy...")

Mentioning in passing "naturally, 4 or more engines" reveals the misunderstanding of how risk works.  If an engine can fail once in N flights, then two of them can both fail once in  N x N flights, three of them can fail once in N x N x N flights, and so on.  Adding more engines lowers the risk of failure, but can never drive it to zero.  There is no human activity which is perfectly, completely, 100.000% safe. And commercial aviation in the USA is about as safe an activity as humans have achieved.

@Coron, modern cars are far more reliable than old ones, yet they still break down. We don't say 'they're reliable until they aren't'. Reliability is a statistic, safety is a statistic, safer flight means there's less likelihood of something going wrong. However, you probably know this, as you almost certainly know that achieving 100% safety is impossible, yet you still asked the question. I suspect that's why you have so many downvotes.

The acceptable standard for risk of a complete airframe loss following a single failure event, like a structural break, or critical system failure, is 10⁻⁹, or one in one billion. That is the FAR 25 standard for transport category airplanes (basically one total loss crash in one billion flights, resulting from a single mechanical/electrical/structural event, is the acceptable standard that you design to).
The risk is determined by mathematical analysis of the affected system and follow-on effects triggered by an initiating event. If you can't a achieve 10⁻⁹ probability, you have to add redundancy, like a backup system or component, or a secondary load path in a structure.
That value is a trade-off between safety and useability.
You can get that number to an even lower probability if you really want to, say one in a trillion, but the plane will be so heavy and costly to operate it's not worth the trouble. And to get the probability to zero is impossible from a practical standpoint, unless the plane just sits in a museum.
As it is, crashes due to single element failures are so rare as to be not worth accounting for. (737 MAX fiasco was rooted in a basic defect of the safety analysis itself and the system architecture designed around it, combined with insufficient oversight, so it can be considered an anomaly from a design perspective).

An engine failure in a twin jet is entirely survivable, but only if the crew follows proper procedures, beginning with "maintain aircraft control" and proceeding from there. The NTSB has stated that both Max aircraft that crashed were entirely flyable, if only the two crews had followed the proper procedures. Boeing did many things wrong in implementing MCAS, but even with all of that, the planes were every bit as flyable as one that experienced a V1 cut or a manual reversion or any number of other things that are known to occur with some (low, but non-zero) regularity.

I agree, but the architecture defect can be considered to have increased the probability to more than one in a billion. Had the safety analysis been done properly, there would have been two AOA inputs and they'd have to live with a reliability hit and probably lose the in-the-background-operating concept requiring no training. They were piggybacking the safety analysis on the Stab Runaway failure mode.


text:
How do aisle lights show the direction to exits?

Lights in the aisle will guide you towards an exit.

I've sat through a lot of safety briefings (for commercial scheduled passenger flights) and always found this sentence especially uninformative. Usually the cabin crew pantomime will include some vague gestures towards the floor of the aisles at this point, but even with airlines that use pre-produced videos for their briefings it seems that the video never actually shows those guiding lights in action.
Are they moving dots of light in the floor that chase towards the nearest exit row? Are they fixed lights that are shaped like arrows, pointing to the exits? Or just a strip of light that will tell me, "here is the aisle", but I'll need to figure out by myself which way along it to crawl?

There’s a door at both front and rear of the aircraft, just follow the strips and you’ll find a door.

@Notts90 Except the Boeing 747 upper deck and lower deck nose section, which is why that design is considered obsolete and prohibited by certification standards.

@user71659 there’s an exception to every rule lol but as you say, they’re obsolete designs and have you ever actually been in one? They’re not exactly big areas so it’d be hard to go the wrong way.

I suspect that the lighting would deliberately not direct you to a particular exit as it may not be open. Pre-flight instruction is to familiarise yourself with the nearest exits in front and behind and then you make the decision (unless otherwise instructed).

@Notts90: Sure - if they're not damaged, underwater, blocked by incapacitated passengers or fire. Hence my comment.

@Notts90: Exatly. That's why they don't give direction. Read my original comment again. I think you've missed something.

In the typical safety briefing, there is normally a statement to look around you to locate the nearest exits and a reminder that it may be behind you.  If you did that, you'll know whether to go forward or aft to find the exit.
As for the floor lighting, 757toga's answer show an example of photoluminescent lighting elements.  They have special considerations, primarily assuring they are adequatey "charged".  The FAA addresses demonstrating compliance of them in AC 25.812-2.
Most older systems use a series of lights spaced at regular intervals.  Lights are white along most of the aisle and are red adjacent to the exit rows.  So follow the white lights until you reach red lights where you can exit.  Compliance information for these systems are in AC 25.812-1A.


text:
lCAO level occupancy
As a radar controller, can you clear an aircraft to a level previously occupied by another one in a way that you don't have 1000ft vertical separation between target Mode C indications as long as the following is fulfilled?
The question stems from the following paragraph in ICAO Doc 8.5.5.2.3:
"Aircraft vacating a level. An aircraft cleared to leave a level is considered to have commenced its manoeuvre and vacated the previously occupied level when the pressure-altitude-derived level information indicates a change of more than 90 m (300 ft) in the anticipated direction from its previously assigned level."

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer.

This question is way too broad.

Good edit - that narrows the scope of the question very nicely. Thank you for focusing your question!

No, you still need vertical separation:
5.3.4.1 An aircraft may be cleared to a level previously occupied by another aircraft after the latter has reported
vacating it, except when:
a) severe turbulence is known to exist;
b) the higher aircraft is effecting a cruise climb; or
c) the difference in aircraft performance is such that less than the applicable separation minimum may result;
in which case such clearance shall be withheld until the aircraft vacating the level has reported at or passing another level
separated by the required minimum.

What if the aircraft performances are similar and the reason is that the other one climbs/descend faster? To my understanding, in a non-radar procedural environment, there is no way of knowing if the actual 1000ft separation exists but you can clear the other one to the level that the other one reports vacating. This would mean that you can be more flexible without a radar than with a radar.


text:
Does ATC use mode S addresses to identify planes?
By design, Mode S surveillance radar equipment uses global 24-bit airframe addresses to keep track of the aircraft it is tracking.
Are these addresses also used by higher levels of the ATC system, such as to fill in call signs, flight plans and so forth automatically when the plane first appears in a controller's domain? Or does that still depend on ATC assigning 12-bit squawk codes that pilots set manually?
Does the Mode S address appear in a flight plan when filed?

The Mode S address is not used for identification of aircraft in the higher levels of the ATC system such as the Flight Data Processing System.
Mostly the assigned 12 bit code (also known as Mode A code or squawk code) is used to correlate a radar track to a flight plan. The major exception is that in Europe, when the Mode A code is set to 1000 (octal notation), the Mode-S downlinked Aircraft Identity (ACID) is used for flight plan correlation. This is to free up Mode A codes. Usually planned flights are assigned discrete Mode A codes but using ACID / Flight ID correlation, multiple aircraft on a flight plan in the same area can use Mode A code 1000.
The downlinked ACID must be equal to the Flight ID used to file the flight plan.
The Mode S 24 bit address is only used in low level systems; in the Mode S radar, in multilateration systems, in ADS-B receivers and to some extend in tracking systems.

The FAA document I found (see other answer) seems to imply that the ACID is also used by Canadian and Australian ATC in similar ways.

@HenningMakholm That's is correct. As far as I know the ACID is used in Canada and Australia only for correlating ADS-B tracks to flight plans, not for Mode-S radar tracks. I am not 100% sure on that though.

(Self-answer after some additional research).
It looks like the 24-bit addresses are not intended for such identification. Instead the Mode S protocol contains a way for the ATC radar to direct a transponder (identified by a 24-bit address) to send its call sign (known as "aircraft identification" in ICAO Annex 10.IV) piggybacked on a normal mode S altitude/squawk reply, coded as up to 8 alphanumeric characters.
It stands to reason that this is what higher-level ATC functions are based on.
Here is one source saying this is the case. It also implies that (some) ATC facilities don't normally assign discrete squawk codes to flights with working Mode S transponders.
(It's not clear to me why the FAA document says the FLT ID is only 7 characters; the data format defined by Annex 10 has room for 8).

This depends on the specific Air Traffic Navigation Service (ATNS) provider providing services and the equipment the controllers are equipped with. US-based FAA controllers actually are mostly unaware of which types of surveillance data are currently contributing to the position the system is plotting aircraft on their displays or scopes.
While they have access to all elements of ADS-B data associated with an aircraft which has been received, the need to query any beyond what is included with a legacy flight strip would be the exception, not the rule. The FAA maintains the world's largest and most complex integrated air traffic surveillance system which offers multiple tiers of aircraft tracking capabilities. This network of air traffic surveillance data sources offer coverage within the vast majority of the US National Airspace System (NAS) designated as Controlled Airspace (Class E, D, C, B, & A).
The FAA does maintain a database of all US registered Mode-S 24-bit aircraft address codes, colloquially referred to as "Aircraft Hex Codes". As a function of the many Bilateral and Multilateral Aviation Safety Agreements entered into with a number of foreign nation states, the FAA also populates this database with the Mode-S Hex Code provided by these foreign Civil Aviation Authorities (CAAs) with regularly received updates.
Nearly all FAA ATC surveillance functions associated with an aircraft's Hex-Code during normal operations are automated and seamless to the controller's display or scope. These functions include the auto population of registration number, aircraft type, and last reported equipment codes, etc into the track data blocks of nonparticipating aircraft, among others.
Your question specifically asks about tracking aircraft movements using these Mode-S Hex Codes. As far as the US FAA's policy, the answer is an unquestioning YES! All air traffic track data, to include all elements of ADS-B data are recorded and retained for a range of defined duration as dictated by specific facility and role. If there is a request or need to retain any set or portion of FAA AT data beyond those disposal time-frames, this can be done indefinitely.
Every nation state CAA and ATNS provider would need to be queried individually to determine the extent of their use of collected Mode-S Hex Code data. The only specific detail I'm aware of is that the ATNS providers located in the UK (NATS) and some parts of the EU (EuroControl) generally seem to be more aware of the Hex-Codes associated with the aircraft under their control. In fact, they are known to recognize and take notice when an aircraft Hex-Code mismatch is operating within their specific sectors. An aircraft Hex-Code mismatch occurs when the aircraft's reported, filed, or communicated registration number can't be reconciled with the Mode-S Hex-Code being used and transmitted and/or the aircraft records database they maintain.
Probably more than you wanted but I'm not one for brevity!

2 things: 1. Eurocontrol is NOT the ANSP for Europe. It’s the ANSP for upper airspace Netherlands, Belgium, Luxembourg. ANSPs of (for example) Germany are DFS or of Italy ENAV! 2. You are talking about „HEX Codes“ all the time. At least in Germany that’s no way to identify any aircraft. Every Mode S Transponder either has a given FLT ID which was entered during installation or a changeable FLT ID (eg airliners). The systems work with this FLT ID. If an aircraft is squawking 1000 we will obtain idenfication using this FLT ID and comparing it to the according FLT ID in the submitted flightplans.

Cont.: The „CSMM“ system you refer to in the last part of your answer also does NOT compare the sent HEX with the stored HEX - it compares the FLT ID sent by the transponder with the FLT ID filed in the FPL. Also, the consequences are certainly not „usually nothing“. If an aircraft with wrong FLT ID is detected in your sector you have to advise the pilot who shall correct it. If she fails to correct it ATC must not identify this aircraft using squawk 1000 and we have to assign a discrete code. Reason being a mismatch btw FPL FLT ID and Mode S FLT ID won‘t correlate the target to a FPL.

@pcfreakxx You're absolutely right in both instances. I read the FAA order a little too quickly. My comment about 'usually nothing' was meant in a regulatory enforcement way. But that's unclear. I'll go ahead and modify the answer, good catches.


text:
Does currency in an aircraft requiring a type rating provide currency for same category and class?
If a pilot has basic currency to carry passengers in an aircraft requiring a type rating, say a Boeing 737, does that mean the pilot is also current in an aircraft in the same category and class (AMEL) that does not require a type rating, e.g. Diamond DA42?
61.57 has the caveat "If a type rating is required". So the question is whether that caveat means that the type is not relevant for considering currency in the DA42. Which would suggest that for the DA42 currency you need only consider flights in the same category and class so any flights in an AMEL (regardless of type) would count.

I believe that is correct, but insurance companies may have other ideas...